chore(deps): bump slackapi/slack-github-action from 1.26.0 to 2.1.1 (#1143)

Bumps [slackapi/slack-github-action](https://github.com/slackapi/slack-github-action) from 1.26.0 to 2.1.1.
- [Release notes](https://github.com/slackapi/slack-github-action/releases)
- [Commits](slackapi/slack-github-action@v1.26.0...v2.1.1)

---
updated-dependencies:
- dependency-name: slackapi/slack-github-action
  dependency-version: 2.1.1
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/update-release-notes.yaml

@@ -46,7 +46,7 @@ jobs:
 
     - name: Slack Notification
       id: slack
-      uses: slackapi/slack-github-action@v1.26.0
+      uses: slackapi/slack-github-action@v2.1.1
       with: 
         payload: "{\"message\":\"Pull request #${{steps.cpr.outputs.pull-request-number }} is ready for kURL.sh release notes: ${{steps.cpr.outputs.pull-request-url}}\",\"version\":\"${{ steps.release-notes.outputs.parsed_kurl_version }}\"}" 
       env: